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Abstract Background Reducing socioeconomic inequalities in obesity is a public health priority. Limited research exists on the role of neighbourhood environmental attributes in mitigating these inequalities. However, it has been shown that neighbourhoods with more greenery tend to have lower levels of socioeconomic inequalities in non-obesity health outcomes. We examined whether neighbourhood greenery moderates the association of area-level socioeconomic status (SES) with waist circumference. Methods Data from 3,261 middle-aged and older adults who participated in a national cohort study conducted in Australia (2011–12) were used. The outcome was objectively measured waist circumference. For area-level SES, a composite index of disadvantage based on census data was used. We used two measures of neighbourhood greenery: mean greenness and geographic size of greenspace. They were assessed using the Normalized Difference Vegetation Index (NDVI) within 0.5, 1, and 2 km radius buffers around participants’ homes. The mean NDVI value within each buffer area was used for the former, and the geographic size of the area with NDVI ≥ 0.6 (dense greenery) was used for the latter. Results There was a significant negative association between area-level SES and waist circumference: one standard deviation higher score in the area-level SES indicator (less disadvantage) was associated with 1.76 cm (95% CI: -2.68, -0.83) lower waist circumference. Analyses stratified by greenery levels found similar significant associations in the areas with low and high levels of greenery but not in the areas with medium levels of greenery for both greenery measures within 1 km and 2 km buffers. Conclusions Consistent with previous studies, our study found that participants living in disadvantaged suburbs were likely to have a larger waist circumference than those living in advantaged suburbs. However, we also found that such socioeconomic inequalities in obesity were mitigated in the areas with medium levels of greenery for this sample of Australian adults. Our findings suggest that there may be an optimum level of greenery where inequalities in obesity are alleviated. Further research is needed to understand the mechanisms underlying these findings.

Abstract Individual-level analyses have consistently shown associations of travel behaviours with obesity-related measures. However, transport planning policies often target areas rather than individuals. To better inform transport-related policies and initiatives for obesity prevention, area-level relationships need to be investigated. This study linked data from two travel surveys with data from the Australian National Health Survey at the level of Population Health Areas (PHAs) and examined to what extent area-level travel behaviours metrics (prevalence of active travel, mixed travel and sedentary travel, diversity of travel modes) were associated with the rate of high waist circumference. Data from 51,987 travel survey participants were aggregated into 327 PHAs. Bayesian conditional autoregressive models were used to account for spatial autocorrelation. It was found that statistically replacing participants who relied on cars for travel (without walking/cycling) with those engaging in 30+ min/d of walking/cycling (without car use) was associated with a lower rate of high waist circumference. Areas with greater diversity of travel modes (mix of walking/cycling, car use, public transport use) also had lower prevalence of high waist circumference. This data-linkage study suggests that area-level transport planning strategies addressing car dependency, shifting car use to walking/cycling over 30 min/d, may help to reduce obesity.

Abstract Background Living in walkable neighborhoods may provide long-term cardio-metabolic health benefits to residents. Little empirical research has examined the behavioral mechanisms in this relationship. In this longitudinal study, we examined the potential mediating role of physical activity (baseline and 12-year change) in the relationships of neighborhood walkability with 12-year changes in cardio-metabolic risk markers. Methods The Australian Diabetes, Obesity and Lifestyle study collected data from adults, initially aged 25+ years, in 1999–2000, 2004–05, and 2011–12. We used 12-year follow-up data from 2023 participants who did not change their address during the study period. Outcomes were 12-year changes in waist circumference, weight, systolic and diastolic blood pressure, fasting and 2-h postload plasma glucose, high-density lipoprotein cholesterol, and triglycerides. A walkability index was calculated, using dwelling density, intersection density, and destination density, within 1 km street-network buffers around participants’ homes. Spatial data for calculating these measures were sourced around the second follow-up period. Physical activity was assessed by self-reported time spent in moderate-to-vigorous physical activity (including walking). Multilevel models, adjusting for potential confounders, were used to examine the total and indirect relationships. The joint-significance test was used to assess mediation. Results There was evidence for relationships of higher walkability with smaller increases in weight (P = 0.020), systolic blood pressure (P

Background Population densities of many cities are increasing rapidly, with the potential for impacts on cardiovascular health. This longitudinal study examined the potential impact of population‐density increases in urban areas (urban densification) on cardiovascular risk markers among Australian adults. Methods and Results Data were from the Australian Diabetes, Obesity and Lifestyle Study, in which adult participants’ cardiovascular risk markers were collected in 3 waves (in 1999–2000, 2004–2005, and 2011–2012). We included 2354 participants with a mean age of 51 years at baseline who did not change their residence during the study period. Outcomes were 12‐year changes in waist circumference, weight, systolic and diastolic blood pressure, fasting and 2‐hour postload plasma glucose, high‐density lipoprotein cholesterol, and triglycerides. The exposure was neighborhood population densification, defined as 12‐year change in population density within a 1‐km radius buffer around the participant’s home. Multilevel linear growth models, adjusting for potential confounders, were used to examine the relationships. Each 1% annual increase in population density was related with smaller increases in waist circumference (b=−0.043 cm/y; 95% CI, −0.065 to −0.021 [P